dynamic panel content hidden by the surrounding content

I nested a dynamic panel of a drop-down menu (with many options) that has multiple states inside a larger dynamic panel, also with multiple states. When user clicks on the nested drop-down menu, the menu options extend beyond the parent panel borders, and becomes hidden beneath the content below the parent panel, even after moving the nested panel to the front (z-axis). How can I get the expanded nested panel content to display above the surrounding content?